Greenhouse gas concentrations

Carbon dioxide concentration in the atmosphere

Carbon dioxide (CO₂) is the single most important greenhouse gas. It is responsible for approximately 65 % of the radiative forcing that is currently observed.^{Footnote 1}

Key results

• Globally, annual average carbon dioxide (CO₂) concentrations increased by 22%, from 338.9 parts per million (ppm) to 412.4 ppm between 1980 to 2020
• Over the period spanning 1976 to 2020, the annual average concentration of CO₂ increased by 24%, from 333.4 parts per million (ppm) to 415.0 ppm
• In 2020, the average concentration of CO₂ in Canada was 415.0 ppm, up from 412.3 ppm in 2019
• Annual changes of CO₂ concentrations observed in Canada are similar to changes observed globally

Carbon dioxide concentration, Canada and global, 1976 to 2020

How this indicator was calculated

Note: From 1976 to 1999, averages were calculated based on data from 2 to 3 sampling stations. Since 1999, data from 5 sampling stations are used to represent CO₂ concentrations. Global annual averages are based on measurements from sampling stations that are part of the Global Greenhouse Gas Reference Network.
Source: Environment and Climate Change Canada (2021) Climate Research Division, Canadian Greenhouse Gas Measurement Program and National Oceanic and Atmospheric Administration (2021) Global Monitoring Laboratory - Trends in Atmospheric Carbon Dioxide.

In 2020, the global average concentration of CO₂ reached a new high of 412.4 ppm, up from 410.1 ppm in 2019. Prior to 1750, which was known as the pre-industrial era, global CO₂ concentrations were about 278 ppm.^{Footnote 2} 

In Canada, the annual change in CO₂ has increased from around 1.5 ppm per year in the 1990s to over 2 ppm per year in the last decade. Seasonal cycles can also be observed with lower concentrations in summer due to photosynthetic uptake (plants remove CO₂ from the atmosphere) and higher concentrations in winter (plants release CO₂ by respiration).

The confinement measures introduced in 2020 due to the pandemic created an industrial slowdown and important reductions in travel by air and land. This new situation resulted in a reduction in anthropogenic CO₂ emissions. Preliminary estimates anticipate a reduction of between 4.2% and 7.5% compared to 2019 CO₂ emissions. However, such a reduction in emissions will not have a significant effect on the global CO₂ average concentration and will only slightly slow down the rate of increase of the global CO₂ concentration. The impact on the CO₂ concentration is expected to be smaller than, or at most, similar to the natural year-to-year fluctuations.^{Footnote 3} 

Methane concentration in the atmosphere

Methane (CH₄) is the second most important greenhouse gas generated by human activity. It is currently responsible for approximately 17 % of the radiative forcing.^{Footnote 1}

Key results

• Globally, annual average methane (CH₄) concentrations increased by 13%, from 1 670 parts per billion (ppb) to 1 879 ppb between 1986 to 2020
• Over the period spanning 1986 to 2020, the annual average concentration of CH₄ increased by 11%, from 1 764 ppb to 1 965 ppb at sites in Canada
• In 2020, the average concentration of CH₄ was 1 965 ppb, up from 1952 ppb in 2019 in Canada
•  Annual changes in observed CH₄ concentrations in Canada are similar to annual changes observed over the globe, but the magnitude is typically around 80 ppb higher, due to greater abundance of both natural- and human-caused sources of methane in the northern hemisphere

Methane concentration, Canada and global, 1986 to 2020

How this indicator was calculated

Note: From 1986 to 1999, averages were calculated based on data from 1 to 2 sampling stations. Since 1999, data from 5 sampling stations are used to represent CH₄ concentrations. Global annual averages are based on measurements from sampling stations that are part of the Global Greenhouse Gas Reference Network.
Source: Environment and Climate Change Canada (2021) Climate Research Division, Canadian Greenhouse Gas Measurement Program and National Oceanic and Atmospheric Administration (2021) Global Monitoring Laboratory - Trends in Atmospheric Carbon Dioxide.

In 2020, the global average concentration of CH₄ reached a new high of 1 879 ppb, an increase of 13 ppb from 2019. This increase is higher than the increase of 9 ppb observed in the period from 2018 to 2019 and the average annual increase over the past decade. Pre-industrial global CH₄ concentrations were about 720 ppb.^{Footnote 2}  Footnote

From 2007 to 2020, average increases in CH₄ in Canada were 8 ppb per year. Although no definitive causes have been identified to explain this increase, stable isotope^{Footnote 4}   measurements of atmospheric CH₄ strongly suggest that increases in wetland emissions in the tropics may be responsible.

Methane concentrations are higher in the northern hemisphere because both natural and human caused sources of methane are more abundant there. Globally, approximately 40% of the CH₄ emitted to the atmosphere is from natural sources such as wetlands. The remaining 60% of emissions are due to anthropogenic (human caused) sources such as cattle ranching, agriculture, fossil fuels and landfills.

About the indicators

What the indicators measure

The indicators show the trends in concentrations for 2 greenhouse gases: carbon dioxide (CO₂) and methane (CH₄). Concentrations are presented on monthly and annual bases for Canada. The indicators also include the global annual average concentrations. 

Why these indicators are important

Greenhouse gases trap heat in the Earth's atmosphere, just as the glass of a greenhouse keeps warm air inside. Human activity increases the amount of GHGs in the atmosphere, contributing to a warming of the Earth's surface. This is called the enhanced greenhouse effect. The release of GHGs and their increasing concentrations in the atmosphere are having significant impacts on the environment, human health and the economy. Consult Greenhouse gas emissions: drivers and impacts for information on the human health, environmental and economic impacts of greenhouse gas emissions.

These indicators serve to identify trends and seasonal variability of carbon dioxide and methane concentrations in Canada. They provide a coherent and consistent picture of the current and past states of these 2 greenhouse gases in the atmosphere, as a result of changing atmospheric transport patterns, emissions from natural sources and emissions to the atmosphere due to human activities.

GHG measurements improve our understanding of natural and anthropogenic sources of GHGs, the role of GHGs in warming the atmosphere, as well as the processes that govern the transport and fate of GHGs in the biosphere. GHG measurements in the atmosphere complement other key indicators used to assess progress in mitigating climate change by reducing GHG emissions. Since GHGs are long-lived in the atmosphere, atmospheric measurements are an indicator of the global and domestic efforts to date to address GHG emissions.

Related indicators

The Greenhouse gas emissions indicators report trends in total anthropogenic (human-made) GHG emissions at the national level, per person and per unit gross domestic product, by province and territory and by economic sector.

The Global greenhouse gas emissions indicator provides a global perspective on Canada's share of global GHG emissions.

The Carbon dioxide emissions from a consumption perspective indicator shows the impact of Canada's consumption of goods and services, regardless of where they are produced, on the levels of carbon dioxide released into the atmosphere.

The Greenhouse gas emissions projections indicator provides an overview of Canada's projected GHG emissions up to 2030.

The Greenhouse gas emissions from large facilities indicator reports GHG emissions from the largest GHG emitters in Canada (industrial and other types of facilities).

Data sources and methods

Data sources

Concentration data used for these indicators were retrieved from the Canadian Greenhouse Gas Measurement Program of the Climate Research Division of Environment and Climate Change Canada. The indicators are calculated using the greenhouse gas concentrations measured at the Alert (NU), Sable Island (NS), Estevan/Cape St. James (BC), Fraserdale (ON) and Candle Lake/East Trout Lake (SK) monitoring stations. The final ambient concentrations of carbon dioxide (CO₂) and methane (CH₄) are averaged to estimate the annual and monthly indicators values.

Global average annual concentrations were obtained from the National Oceanic and Atmospheric Administration's Global Monitoring Laboratory (NOAA/GML), which developed the Carbon Cycle Greenhouse Gases research program. 

More information

Canadian Greenhouse Gas Monitoring Network

Environment and Climate Change Canada has been continually building a long-term observation network for atmospheric measurements of CO₂, CH₄ and carbon monoxide (CO), which currently stands at 16 core continuous observational ground-based sites. These sites are spread across the country in coastal, interior and arctic regions, with the aim of providing high quality data to observe and monitor natural sources and sinks, and anthropogenic (human-caused) sources of greenhouse gases in Canada. 

The data used for the indicators were measured at 3 coastal sites and 2 mid-continental forest sites that are part of the Canadian Greenhouse Gas Monitoring Network.

The coastal sites are located at:

• Alert (NU), on Ellesmere Island in the Canadian high Arctic,
• Sable Island (NS), located in the Atlantic Ocean,
• Estevan Point (BC), a lighthouse station located on the coastline of Vancouver Island. Estevan Point became the replacement station for Cape St. James in 1992, when the weather station at Cape St. James was automated and no longer required a manned presence on site.

The mid-continental forest monitoring stations are situated in:

• Fraserdale (ON), located 150 km north of Timmins (ON),
• Candle Lake (SK), located 150 km north-east of Prince Albert (SK). After 3 years of operation, East Trout Lake became the replacement station for Candle Lake in 2005.

The Alert Station is also an official World Meteorological Organization Global Atmosphere Watch Program (WMO-GAW) station, one of 26 global stations around the world. Alert is the most northerly site in the WMO-GAW Network. The Alert site is also one of three sites, along with Mauna Loa and Cape Grim, which have been identified by the WMO-GAW as official greenhouse gas intercomparison sites.

Greenhouse gas concentration monitoring stations in Canada, 2020

Data table for the long description

Greenhouse gas concentration monitoring stations in Canada, 2020

Start date	Site name (3 letter station code)	Coordinates	Elevation (asl)	Intake height	Insitu parameters	Insitu instrumentation	Flask sampling frequency (for CO2, CH4, CO, N2O, SF6)
March, 1975	Sable Island, Nova Scotia (WSA)	43.932237N, 60.009275W	5m	25m	CO2, CH4, CO	NDIR, GC, CRDS	Single flask every three days
July, 1975	Alert, Nunavut (ALT)	82.450833N, 62.507222W	200m	10m	CO2, CH4, CO, N2O	NDIR, GC, CRDS OA-ICOS	One pair of flasks eachweek
January, 1990	Fraserdale, Ontario (FRD)	49.875222N, 81.570083W	210m	40m	CO2,CH4, CO, N2O, SF6	NDIR, GC, CRDS	Single flask once per week (in the afternoon)
June, 1992	Estevan Point, British Columbia (ESP)	49.382954N, 126.544101W	7m	40m	CO2, CH4, CO	NDIR, GC, CRDS	One pair of flasks once per week
June, 2002	Candle Lake, Saskatchewan (CDL)	53.987108N, 105.117939W	600m	30m	CO2, CH4, CO	NDIR, GC
October, 2003	Downsview, Ontario (DWN)	43.780491N, 79.468010W	198m	20m	CO2,CH4, CO, N2O, SF6, CO2	NDIR, GC, CRDS, OA-ICOS	Single flask once per week
March, 2005	Egbert, Ontario (EGB)	44.231037N, 79.783834W	251m	3m, 25m	CO2,CH4, CO, N2O, SF6, Radon	NDIR, GC, CRDS	One pair of flasks every other week
August, 2005	East Trout Lake, Saskatchewan(ETL)	54.354130N, 104.986835W	493m	105m	CO2,CH4, CO, N2O, SF6	NDIR, GC, CRDS	Single flask once per week (in the afternoon
April, 2007	Churchill, Manitoba (CHU)	58.737885N, 93.819403W	29m	60m	CO2, CH4, CO	CRDS	Single flask twice per week (in the afternoon)
April, 2007	Lac La Biche, Alberta (LLB)	54.953851N, 112.466646W	540m	10m, 50m	CO2, CH4, CO	NDIR, GC, CRDS	NOAA Sampling
August, 2007	Chibougamau, Quebec (CHB)	49.692510N, 74.342296W	393m	30m	CO2, CH4, CO	NDIR, GC
October, 2009	Bratt’s Lake, Saskatchewan (BRA)	50.201683N, 104.711268W	595m	35m	CO2, CH4, CO	CRDS	Single flask once per week
January, 2010	Esther, Alberta (EST)	51.670681N, 110.206009W	707m	3m, 50m	CO2, CH4 CO	CRDS
October, 2010	Behchoko, Northwest Territories (BCK)	62.798087N, 115.919426W	160m	60m	CO2, CH4, CO	CRDS
December, 2011	Chapais, Quebec (CPS)	49.822317N, 74.975274W	391m	8m, 40m	CO2, CH4	CRDS	Single flask once per week
February, 2012	Inuvik, Northwest Territories (INK)	68.317817N, 133.534232W	113m	10m	CO2, CH4 CO	CRDS	Single flask once per week
December, 2012	Cambridge Bay, Northwest Territories (CBY)	69.128418N, 105.057709W	35m	12m	CO2, CH4, CO	CRDS	Single flask once per week
March, 2014	Abbotsford, British Columbia (ABT)	49.011386N, 122.335332W	60m	33m	CO2, CH4, CO, N2O, Radon	CRDS, OA-ICOS	Single flask once per week

Note: The map displays the 16 primary long-term greenhouse gas concentration monitoring stations in Canada. The 5 sites of Alert (NU), Sable Island (NS), Fraserdale (ON) Candle Lake/East Trout Lake (SK) and Cape St. James/Estevan Point used in the indicators are shown using pink stars. The 3 terminated stations of Cape St. James, Candle Lake and Chibougamau are also shown.
Source: Environment and Climate Change Canada (2021) Climate Research Division, Canadian Greenhouse Gas Measurement Program.

Temporal coverage

The indicator presenting the carbon dioxide (CO₂) concentrations covers the period from 1976 to 2020. However, no data on global CO₂ concentrations were available from 1976 to 1980.

The methane (CH₄) concentrations were calculated using data for the years 1986 to 2020.

Data availability

Greenhouse gas observations at the 5 monitoring stations are all currently monitored continuously and provide hourly, daily and monthly data. Prior to 1988, carbon dioxide (CO₂) observations were monitored using weekly grab (flask) sampling procedures.

Greenhouse gas observations at the 5 monitoring stations are all currently monitored continuously and provide hourly, daily and monthly data. Prior to 1988, carbon dioxide (CO₂) observations were monitored using weekly grab (flask) sampling procedures.

Data availability varies by station and by greenhouse gas over time. The following table shows the time periods for which data are available for each greenhouse gas at the 5 monitoring stations. 

Data availability by greenhouse gas and monitoring station

Greenhouse gas	Time period	Monitoring stations
Carbon dioxide	1976 to 2020	Alert and Sable Island
Carbon dioxide	1979 to 2020	Cape St. James/Estevan Point
Carbon dioxide	1999 to 2020	Fraserdale
Carbon dioxide	2002 to 2020	Candle Lake/East Trout Lake
Methane	1985 to 2020	Alert
Methane	1990 to 2020	Fraserdale
Methane	1999 to 2020	Sable Island, Cape St. James/Estevan Point
Methane	2002 to 2020	Candle Lake/East Trout Lake

Global concentrations from the Carbon Cycle Greenhouse Gases research program

The Carbon Cycle Greenhouse Gases (CCGG) research program from the National Oceanic and Atmospheric Administration's Global Monitoring Laboratory operates the Global Greenhouse Gas Reference Network, measuring the atmospheric distribution and trends of the 3 main long-term drivers of climate change, carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O), as well as carbon monoxide (CO). 

Methods

The monthly and annual concentrations are an average of the daily values over the corresponding period of time.

Caveats and limitations

Given greenhouse gas (GHG) are long-lived in the atmosphere and are transported globally from the site of emission, these indicators are an integrated measure of global and domestic GHG emissions to the atmosphere. For more information on Canada’s emissions, and to assess Canada’s progress in reducing its emissions, please refer to the related indicators which present information on greenhouse gas emissions in Canada.

For both carbon dioxide and methane concentrations, the number of monitoring stations used in the analyses increased in 1999. The change in the number of monitoring sites may have influenced calculations of the average values and make it difficult to compare trends prior and post 1999. In the particular case of methane concentrations, values prior to 1999 were based on data from 1 station and may not be representative of the concentrations over Canada. 

References

Environment and Climate change Canada (2017) Canadian Greenhouse Gas Measurement Program. Retrieved on November 19, 2020.

Intergovernmental Panel on Climate Change (2013) Climate change 2013: The physical science basis. contribution of working group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. Retrieved on November 19, 2020.

National Oceanic and Atmospheric Administration (2020) Carbon cycle greenhouse gases. Retrieved on November 19, 2020.

National Oceanic and Atmospheric Administration (2021) Global monitoring laboratory - Trends in atmospheric carbon dioxide. Retrieved on June 1, 2021.

World Data Centre for Greenhouse Gases (2018) Data archive. Retrieved on November 19, 2020.

World Meteorological Organization (2019) WMO Greenhouse Gases Bulletin. Retrieved on October 27, 2020.

World Meteorological Organization (2020) Global Atmosphere Watch. Retrieved on November 19, 2020.

World Meteorological Organization (2020) WMO Greenhouse Gases Bulletin. Retrieved on January 26, 2021.

Related information

Canada’s action on climate change

Canada's changing climate report

Climate change

Greenhouse gas emissions

Greenhouse gas emissions: drivers and impacts